THE MUSCLES OF THE LOWER EXTREMITY. 255 



" The tibial head of this muscle at its origin is 

 directly covered by the soleus, while in the aperture 

 existing between the two heads w r e can discern the 

 popliteus. 



" These flexor muscles, and others on both the front 

 and rear of this limb, are moulded upon each other in a 

 manner that can only be justly appreciated by a personal 

 examination. In some the connections are quite feeble, 

 the intervening tissue being easily separable, while in 

 others the intimacy is very close, and great care is de- 

 manded on the part of the investigator to see that the 

 separation is made along the proper divisions. 



" I am convinced from my studies that a greater 

 difference is to be found among the various muscles of 

 birds than we have ever accredited them with, and this 

 fact leads me to believe that the day will come when 

 these differences can be called into play in taxonomy with 

 excellent effect. Perhaps if the myology of the leg is 

 examined as carefully as Professor Garrod examined the 

 muscles of the thigh in this class, fully as many interest- 

 ing and valuable distinctions will come to light. 



"As we pass the muscles we have described for this 

 limb of Geococcyx in review, it will at once be recognized 

 that the list is unusually complete. All the ordinary 

 muscles of the thigh are present as found in birds, and all 

 highly developed. In the leg marked specialization and 

 organization are everywhere evident, while exceptional 

 muscles are here, too, fully represented. 



" This complexity by no means diminishes as we 

 proceed towards the foot, for the arrangement of the 

 tendons as they course down the tarso-metatarsus and 

 the special musculature of this division of the limb is 

 manifestly indicative of high organization. 



" Finally, we have the complex insertional extremities 



